The present invention relates to a method of forming a character font and a figure, which is applied to various devices with an image processing function such as a dot printer and a dot display device.
In a typical conventional method for forming a character font, each character font is defined by a dot pattern of m (rows).times.n (columns) matrix, and each dot constituting the matrix corresponds to each bit of a memory, thereby storing the matrix pattern in the memory. However, this conventional method has the following drawbacks.
1. If a storage pattern, i.e., a basic pattern is enlarged at any magnification, smooth enlargement cannot be performed.
2. Many conversion operations are required to rotate the basic pattern.
3. The memory capacity is increased in proportion to the size (m.times.n) of the basic matrix.
In order to improve the drawback in item 1, there is proposed a prior art method and apparatus for forming each character by combining six different component shapes (U.S. Pat. No. 3,893,100).
This prior art will be briefly described.
Six different component shapes in FIG. 27 are combined to prepare a character pattern in FIG. 28. The six different component shapes are converted to 3-bit codes, respectively. A character is then stored in a matrix form, as shown in FIG. 29.
In this prior art, the following problems are posed when the character pattern is to be enlarged.
1. In four triangular graphic components (010 to 101 in FIG. 27), the inclination of the slope of each component shape is fixed at 45.degree.. In order to set the angle to be variable, a large number of component shapes are required, resulting in impractical applications.
2. Many conversion operations are required to rotate the pattern. For example, in order to rotate the pattern stored in the memory, as shown in FIG. 29, through 90.degree. and to print the rotated pattern, the bits of the fifth column in FIG. 29 must be rearranged to be those of the first row. For this purpose, the pattern codes must be rearranged, as shown in Table 1. In particular, since the pattern codes in FIG. 29 are stored in units of bytes (8 bits), many operations are required to perform rearrangements.
TABLE 1 ______________________________________ Before Rotation After 90.degree. Rotation ______________________________________ 000 .fwdarw. 000 001 .fwdarw. 001 010 .fwdarw. 011 011 .fwdarw. 100 100 .fwdarw. 101 101 .fwdarw. 010 ______________________________________
3. When the character generator size is increased, i.e., when the number of dots constituting a character is increased, the storage capacity and the processing time of the character generator are increased accordingly. According to the conventional method, the memory capacity of m.times.n.times.3 bits is required to store the m (horizontal).times.n (vertical) matrix size regardless of the printing density. When the size of the character generator is increased (e.g., when m or n is increased), the memory capacity of the character generator is inevitably increased. In addition, the processing time is also increased in proportion to the increase in the memory capacity of the character generator.
The size of the character generator tends to be increased to obtain characters with higher printing quality. A matrix of 96.times.96 or larger has been used in practice.